Free-market fundamentalism — the belief that the economy, if left to its own devices, will self-correct in times of stress — is the source of all evil in Russell Brand and Michael Winterbottom’s inflammatory documentary, “The Emperor’s New Clothes.” And the economist Milton Friedman, whose laissez-faire economic theories were embraced by Margaret Thatcher and Ronald Reagan, is portrayed as a kind of Antichrist foreshadowing the global meltdown of 2008.

Mr. Brand, the tousled-haired British comedian, actor and left-wing activist once briefly married to Katy Perry, might be described as Michael Moore with fangs. Instead of a genial, shuffling Everyman, he is an outspoken, fiery-eyed political gadfly preaching revolution. With his shrill, acrid voice, filled with nagging indignation, he wants to goad listeners into taking action. Voting isn’t enough to reverse income inequality, he warns. Active involvement is necessary, he insists, as he spreads his message from a sound truck touring London.

The movie begins with the Hans Christian Andersen tale “The Emperor’s New Clothes,” about two weavers who promise the ruler a new suit that is invisible to those who are stupid or incompetent. As he parades before his subjects, they pretend that he’s dressed in silk and gold until a child in the crowd pipes up and shouts that he isn’t wearing anything at all.

That willful blindness is a metaphor for the behavior of the masses who accept on faith the free-market doctrine, a tenet of which is the unproven “trickle-down” theory that great wealth benefits everyone by seeping down from above.

Mr. Brand indulges in many of the same stunts Mr. Moore has pulled, ambushing bankers and plutocrats and asking them uncomfortable questions, which they brush off. In the most clever running gag, he quizzes a group of schoolchildren with loaded questions about income disparity in Britain, and asks if it’s fair, only to be answered with a resounding “No.” In one assertion, not credited to a source, he declares that if all the money in Britain were divided equally, each person would get 200,000 pounds (about $300,000).

The most infuriating revelations have to do with the system of tax avoidance, by which he says an estimated $21 to $32 trillion are held in offshore tax havens like the Cayman Islands.

“The Emperor’s New Clothes” ends on a positive note, with the true story of how Mr. Brand and fellow activists fought an American equity firm, Westbrook Partners, whose proposed purchase of the New Era Estate, an East London development, became a public relations disaster. Once it was refurbished, the raised rents would have rendered many of the longtime residents homeless. Under pressure, Westbrook backed down.